Syringe.



l. MACGREGOR.

SYRINGE.

APPLICATION FILED MAH. I3. |914.v LmM Patented spt. 3,1918..

EEE 23 m Ey. /7 i i f5 F296 mag/mw 6g 7 M mz nomas nerfs ca Pnow Uma wnsnwcnm. n. r:.

JOHN MACGREGOE, OE BOsTON,'MASSAoHUSETTS, ASSIGNOR, EY MESNE ASSIGNMENTS, e Y To MACGREGOE INSTRUMENT COMPANY, or BOSTON, MASSACHUSETTS, A CORPORA- TION OE MASSACHUSETTS SYEINGE.-

Patented Sept. 3, 1918.

Application filed March 13, 1914. Serial No. 824,523.

To all 'whom it may concern:

Be it known that I, JOHN MAoGREcoR, a citizen of the United States, and a resident of Boston, county of Suffolk, and State of Massachusetts, have invented an Improvement in Syringes, of which the following description, in connection with the `accompanying drawings, is a specification, like characters o n the drawings representing like mining accurately the voluminal contents of:

the syringe,.and for the convenient and efiicient operation thereof. V The character of thel invention may be readily understood by reference to one illustrative embodiment Shown in the accompanying drawings, in which: e Figure 1 is a side elevation partly in section, ofthe illustrative syringe; y

Fig. 2 is a detached detail, a part of the piston stem being shown in section to illustrate a preferred adjustable connection between said stem and the handle;

Fig. 3 is a top view of a preferred form .of handle;

Fig. 4 is a transverse section on the line of Fig. l; and

y Fig. 5 is an enlarged detail showing a preferred form of needle point, to the use of which certain features of the illustrative Isyringe are particularly adapted.

Fig. 6 is a perspective showing the relative positions'A of the hand of an operator and the illustrative' type of handle shown in .Fig..1.

Referring to the drawings, the illustrative syringe comprises a barrel 6 containing Va-piston 7 which closely fits the interior of the barrel, although in sliding contact therewith.

' At the lower end of the barrel is provided a conical seat communicating withan outlet 9 through which the contents of the barrel are ejected, this outlet preferably passing through a tip 10 threaded to receive a hub 11 which carries the cannula 12 of the needle. Y

An annular recess 13 is provided in the lower end of the barrel 6, encircling the tip 10; countersunk in said recess 13 is a metallic packing which may be provided conveniently a tin washer permanently fitted into the recess. When the hub 11 of the needle is secured upon the tip 10 it may be tightened against the metallic packing in the recess 13 so as to foi-1u a hermetic closure between the outlet 9 and the needle.

The concave conical surface of the seat 8 preferably directly intersects the interior cylindrical surface of the barrel 6; in other words, the cylindrical interior surface of the barrel merges directly into the converging conical surface of the seat 8 without any intervening shelf-like surface upon which a minute quantity of the contents of the syringe might lodge and fail of being ejected.

The lower end 14 of the piston 7 is ground in `conical shape to lit precisely upon the seat 8; and the concave conical end of the piston directly intersects the cylindrical eX- terior surface of the piston. Thus the piston as a whole, when in the closed position shown in Fig. l, lits very accurately the interior of the barrel 6 and the seat 8 so that upon the final closing movement ofthe piston the entire contents of the barrel are completely and eHectually expelled, and the outlet 9 is to all intents and purposes hermetically closed in readiness for introducing` an- Y other charge to the barrel by aspiration.

fwidely but still gradually, until the iniiow of the liquid is well under way. This minute ,opening of the needle valve 'at the outset of the aspirating movement is of imporlie tance in that it permits the inflow of the liquid to start more or less graduallyso as to minimize, andjn. tact `practically.eliminate, the tendency igor air to be drawn from the upper part of the barrel past the piston= into the lower liquid containing end of the barrel.V As is well understood in .the art, the presence of air in the barrel. chamber with the liquid is absolutely necessary to be avoided. When the needle. is .inserted in theliquid thereI is7 of course, some infinitesiinal voluineofair inthe bore oit the .needle and the .outlet 9, butthis .is `so small. as to be negligible, and the principal considera-l tion is to ayoid any inflow of air around the piston.v This purpose is eifectnallyserved by the'arrangement described.

The arrangeinent ju'st described, which in andot' .itself avoids any substantial. tendency to. draw in air around` the cylinder 7, obviates .the necessity for a E packing varound the piston stenil andtheijefore the cap 16, which is'preferably employed te close the upperendwoiE the barrel (S and to. give the instrun'ient a iinishedajiipiairancea may encircle thel piston steinfonly loosely.

It has been 1custoinary in certain types of syringe heretofore` used7 to provide a packing7 such as by leather washers or the like, aroundthe piston stein. Any such packing, hongeveigf is subject to practically j complete deterioration in awery short ytime when the parts,I of the Iinstrunient are sterilized by boiling; the heat in boiling promptlydestroys the effectiveness ofthe packingm j 1t will be observed .that thedescribe'd instrument contains no packing which isin any degree `subject i to deterioration from boiling, In fact,y the onlything employed in the nature ola` packing is the preterably metallic washer.13,.countersunk Vin the lower end of the barrel, but thisis, obviously thoroughlyl durable `and unharmed byV boiling.

Tov meet the practical necessityfor boil ing in order lto lsterilize the instruments of the type described,i the barrel, its seat 8, and the tip 10, are preferably integral with earch other,being formed.` of `a jsingle cylinder; and to: suitfthe heavypressure intended to be exerted upon the contents in injecting them 4for purposes of dental anesthesia, Vthe walls of the cylinder- 6 are yof substantial thickness.A The integral character of the barrel .6, Aseat. 8,. and tip lOi also contributes obviously tothe strength of the instrument appropriate to a ljiighpressnre syringe.

The piston stem 15 is'preferaloly graduated to show kin its different positions the in vteriOivOluine of tliechamber o. the barrel below the pistond; The upper ijedgeof the cap16may serve conveniently asthe index lcop.erating with'tliese graduations. When inth'e'position shownin Eig-1, the zero graduation of the `stem :is yopposite the top edge of the cap 16. There isan important relation between these graduations and the ,need-le valve, construction. y ,compri sing the piston end-lai` and its seat `8. The factthat the interior cylindrical'surface of `thebarrel merges directly with the conical concave sur- :tace ott the seat 8, thereby avoiding any lodginent ot the contents and provdingior the coinpletevejection thereofand also the 'functioning oi' this organization to avoid an inflow of air around the pistonrenders it certain thatthe.-inflowi of liquid upon withdrawal oit the pistoir will always accurately |`ill the chan'ilier of Vthe barrel below the piston and'will occupy completely the volume indicated Iby the graduations` on the pistonstem.I k" A For relatively operating the barrel-6 and piston 7., handles 17 and '18 a1e`lprovided. The lhandle `17 is preferably rotatably mountedon the barrel 6 between brazed ,or othernf'isejlxed collars 17? andul".

'lfhehandle 18 (see Fig. 2) has preferably a shank 2O provided with "a donble pitch thread screwing .into the uppert end ci" the piston stein 15. This arrangement permits the handle 18 to be adjusted lengthwise oit' the piston stein to suit hands oi different dimensions and also permits the handle '18 to be adjusted f artlieiyaivay from the handle 17, to permit a better purchase by the operator inthe tinalstr-oke olfthe piston when it is Idesired to complete, an injection. under .heavy pressure.

Preferably the piston 7 .is freely rotatable about its Vown axis in Vthe barrel 6, so that with or without the adjustment provided by the shank 20, both the handle 17 (bein r0- tatably mountedr on the barrel) anc `the handle 1S'are freely rotatablefin relation to the needle 1Q.` A preferred Aformof needle is shown in enlarged "detailiirFig `5, itconsisting olf al minute tube ground` obliquely and unsyn'nnetrically tb provide` a large opening j in combina ti on withl sharp point and sharp edges surroundingfthe opening. Qbvionsly, iii/'heir such1 an iinsyinlnetrical needle is inserted subcutaneou'sly, any twisting of. the needle about itsmlongitndinal Aaxis might cause a substantial cutting` of .the tis sues Lwhich wouldA be Vhighly undesirable. Similarly, if awcurvedneedle of any/ sort were employed any twisting thereof would be highlyl undesirable.` j Any Ltendency to twist ythe needle is minimized by the arrangenient described by whichA eitherhoi` both of the handles `17 and. I18 may be freely rotated in relation to the needle;` andy this arrangement also admits of the operatorsshifting .his hand any yceinfortablepor@convenient` position' j without necessarily twistingg the needle or changing its position in any degree. l

t The described instnuinent ispintenpled to be helddby placingtlie-firs't and second iingers beneath the two ends of the handle 17 and astraddle of the barrel 6, the palm of the hand resting upon the top of the handle 18. The illustrative form of handle shown in Figs. 1 and 8 is especially desirable.

A rounded portion 22 is arranged to be positioned substantially on the median line lengthwise the palm of the hand and about two-thirds of the distance from the knuckles to the wrist. A pommel 23 is arranged to engage the crotch between the thumb and the foreiinger. In plan view as shown in Fig. 3 the pommel 23 is arranged on a line oblique to the length of the handle 22 so that the pommel may stand in substantially the plane of the outer side of the crooked forenger while the remainder of the handle extends across the palm in a direction substantially parallely to the length of the extended thumb. Preferably a depression 24- of considerable depth is provided adjacent the pommel 23 to receive the flesh between the thumb and the knuckle of the forefinger and permit the pommel 23 to engage that portion of the hand firmly to prevent any slipping of the handle 18 relative to the hand, in operation. The adjacent portions of the thumb entering the recess 24 and bearing upon both sides of that recess effectually prevent any slipping of the handle 18 in either direction along its length and the pommel 23 being gripped between the thumb and knuckle of the forenger, is thereby prevented from any transverse slipping. All such features as these are of particular importance in a high pressure syringe whereby anesthetics or the like are intended to be injected under heavy pressure, and necessarily with the greatest precautions against slippage.

It is to be understood that the particular embodiment of the invention described above and shown in the drawings, is disclosed merely for purposes of illustration and the invention is not limited to the particular construction, organization and mode of operation thereof. On the contrary, the invention may be variously embodied, and, while it is desirable that all the features of the invention be used conjointly for the greatest advantage, certain of the features may be used separately, or in sub-combinations.

Claims:

l. A syringe of the character described comprising, in combination, a barrel, a piston in the barrel; a non-symmetrical needle secured to the outlet end of said barrel; and handles upon the barrel and piston respectively and mounted to be freely rotatable relatively to said needle.

2. A syringe of the character described comprising, in combination, a barrel; a piston; means for attachment of a needle at the outlet end of the barrel; and handles on the barrel and piston respectively freely rotatable in relation to said means for attachment of the needle.

3. A syringe of the character described comprising, in combination, a barrel; a piston; a handle on the barrel adapted to be engaged by the operators lingers; and a handle on the piston adapted to rest upon the palm of the operators hand, and having a pommel disposed obliquely in relation to the length of the handle and bent to engage the crotch between the thumb and the forelinger, and provided with a recess of substantial depth between said pommel and the axial line of the piston to receive the fiesh of the hand between the thumb and forenger to prevent slipping of the handle.

4. A syringe of the character described comprising, in combination, a barrel; a piston; a handle on the barrel to be engaged by the operators lingers; and a handle on the piston adapted to rest upon the palm of the operators hand, the surface of the handle to contact with the palm of the hand having a compound curve to fit the conformation of the hand from a point in the crotch between the thumb and foreiinger and a point in substantially the median line of the hand at the base of the thumb.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

JOI-IN MACGREGOR.

Witnesses:

LAUBENGE A. JANNEY, ROBERT I-I. KAMMLER.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. c. 

